Transdermal delivery of drugs has become well established in recent years with the introduction of systems such as NITRO-DUR (Key Pharmaceuticals, Inc.), an aqueous polymeric delivery system containing trinitroglycerol. A lactose free system has recently been provided as shown in Key Pharmaceuticals, Inc. PCT application WO No. 83/00093, published Jan. 20, 1983, "Trinitroglycerol Sustained Release Vehicles and Preparations Therefrom." The anti-anginal activity of trinitroglycerol has been well known for many years, and a sustained release of trinitroglycerol through the skin for systemic activity has been known for several decades, as evidenced by Davis et al, Am. J. Med. Sci., 259-263, (Sept. 1955). NITROL (Kremers-Urban) and NITRO-BID (Marion) have been on the market for some time. Gross et al, Archiv fur Toxikologie, Vol. 18, 199, 331-334 (1960), has noted the sustained release of trinitroglycerol in studies that confirm that trinitroglycerol is delivered through the skin at a steady rate. The rate determining step for trinitroglycerol systems is controlled by the skin itself. Around 1970, various sustained release forms were proposed as exemplified by Zaffaroni, U.S. Pat. No. 3,942,751, although none of the embodiments disclosed were put into use. The methods of the early 1970's focused on what has been termed the "biomedical engineering" approach where different layers are bonded together to provide a metering effect through such combination of layers, explained in Robinson, ed., Sustained and Controlled Release Drug Delivery Systems, pp. 557-594 (New York: Marcel Dekker, 1978). In the late 1970's, Key Pharmaceuticals, Inc., developed the "chemical" matrix system for the delivery for trinitroglycerol, exemplified by Keith et al, U.S. Pat. No. 4,291,015, and its commercial preparation NITRO-DUR. In such a "chemical" system, delivery rates and other parameters are controlled through the constitution of a matrix with appropriate parameters and do not depend upon layering of other materials as in the "biomedical engineering" approach.